Infineon Technologies CY7C136-55NXC

Overview

CY7C136-55NXC from Cypress Semiconductor is a 2K × 8 true dual-port static RAM with independent left/right ports, 55 ns maximum access time, 5 V ±10% supply, and 52-pin PLCC package. It enables simultaneous read access to the same memory location and supports master-mode expansion of data bus width to 16+ bits when paired with CY7C142/CY7C146 slave devices. Used in DSP cache, multiprocessor interconnect, and bit-slice architectures requiring low-latency shared memory.

For engineers reviewing the CY7C136-55NXC datasheet, CY7C136-55NXC pinout, CY7C136-55NXC application, or CY7C136-55NXC equivalent, key selection criteria include dual-port arbitration timing (tBLA = 30 ns), BUSY flag behavior (open-drain, pull-up required), INT interrupt latency (tWINS = 45 ns), and asymmetric standby current (ISB2 = 75 mA with one port active).

Technical Context

The CY7C136-55NXC implements fully asynchronous dual-port operation with independent CE, R/W, and OE controls per port. Its arbitration logic resolves contention via open-drain BUSY flags - asserted when both ports attempt concurrent access to the same address - and supports priority-based port communication using dedicated INT pins on 52-pin PLCC.

It features automatic power-down per port controlled by CE, CMOS-compatible input thresholds (VIH = 2.2 V, VIL = 0.8 V), and four standby current modes (ISB1–ISB4) enabling fine-grained power management. The device operates across commercial (0°C to +70°C) and industrial (–40°C to +85°C) temperature ranges with 5 V ±10% supply.

Key Specifications

Pinout & Package

Package: 52-pin Plastic Leaded Chip Carrier (PLCC), JEDEC MS-018AC, body size 19.1 mm × 19.1 mm, lead pitch 0.5 mm.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar dual-port SRAM applications.

Compared with CY7C136A-55NXC, the original offers identical performance but may differ in wafer lot traceability; versus CY7C146-55NXC, it provides full master functionality including BUSY generation and INT signaling - essential for standalone or master-only implementations.

Availability

CY7C136-55NXC is available at Aetrix Electronics and suitable for DSP cache memory, multiprocessor interconnect, and bit-slice processor systems requiring stable component supply, industrial temperature support, and legacy 5 V compatibility.

Supply support for CY7C136-55NXC includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Cypress Semiconductor (now part of Infineon Technologies) is a U.S.-based semiconductor company specializing in memory, microcontrollers, and programmable logic solutions for industrial, automotive, and communications markets.

CY7C136 belongs to Cypress's legacy dual-port SRAM product line, designed specifically for deterministic, contention-free shared memory in real-time embedded systems with multiple asynchronous masters.

FAQ

Is CY7C136-55NXC pin-compatible with CY7C136-55JC?

Yes - both use identical 52-pin PLCC packaging and share the same pinout, electrical characteristics, and timing specifications. The "NXC" suffix denotes lead-free (Pb-free) construction per JEDEC J-STD-609, while "JC" indicates standard leaded finish; no PCB layout or firmware changes are needed for substitution.

What is the function of the BUSY pin, and why does it require a pull-up resistor?

BUSY is an open-drain output that asserts low when port contention occurs (e.g., both ports access the same address). Because open-drain outputs cannot drive high, a 4.7 kΩ pull-up resistor to VCC is mandatory to establish a valid HIGH logic level during non-contention periods and ensure reliable detection by external logic.

Can CY7C136-55NXC operate in a single-port configuration?

Yes - either port can be disabled by holding its CE pin high, effectively converting the device into a single-port 2K × 8 SRAM with full 55 ns access. However, doing so forfeits dual-port advantages like simultaneous access and inter-port signaling via BUSY/INT, and standby current drops to ISB1 = 35 mA (both ports idle).

How does the INT flag work, and what memory addresses trigger it?

INT asserts when data is written to dedicated interrupt locations: 7FFH (hex) for the left port triggers INTR, and 7FEH for the right port triggers INTL. This hardware-based mechanism enables immediate, low-latency inter-port notification without polling, with guaranteed tWINS ≤ 45 ns from write initiation to INT assertion.